To bolster its free medical photo-sharing app, Toronto startup Figure 1 raised US$4-million in its series A financing round earlier this month, largely driven by New York-based Union Square Ventures, an early investor in Twitter, Tumblr, Zynga and Kickstarter

To bolster its free medical photo-sharing app, Toronto startup Figure 1 raised US$4-million in its series A financing round earlier this month, largely driven by New York-based Union Square Ventures, an early investor in Twitter, Tumblr, Zynga and Kickstarter.

It was a long shot for the venture capital firm, which manages US$1-billion mostly focused in New York and Silicon Valley companies, to reach out to the small Canadian startup in a tweet — and for a Figure 1 intern’s reply to eventually lead to a US$2.5-million cheque.

“So it was really just via Twitter, which is hilarious,” said Gregory Levey, chief executive of Figure 1, recounting the initial exchanges with Andy Weissman, a partner at Union Square Ventures, who helped the company set up its $2-million seed round and introduced it to other investors. Earlier supporters, such as Version One Ventures, Rho Canada Ventures and a handful of angels, again pitched in during the series A round.

Launched in May 2013, the Instagram-like app allows doctors, nurses, surgeons and other healthcare practitioners to upload photos that colleagues anywhere can observe and comment on — but instead of adorable pets, hip selfies and homemade dishes, they are of gruesome skin boils, surgically removed tumours and bloody umbilical cords.

“We thought it would take some time before we really got product-market fit but, within a few days, it just took off,” Mr. Levey said of the app, which now has more than 140,000 users across North America, the United Kingdom, Ireland, Australia and New Zealand and recorded 125 million image views and 70,000 comments.

Mr. Weissman, who now sits on Figure 1’s board of directors, said the company fit Union Square’s so-called investment thesis, which is to support startups that create “large networks of engaged users,” and he plans to draw on his experiences with exited social networking investments such as Twitter and Tumblr.

“They’re doing pretty well. I don’t think anything needs to be fixed,” said Mr. Weissman, who is impressed by the app’s user traction. Unlike other U.S. investors Mr. Levey spoke with, who were pushing for Figure 1 to relocate to Silicon Valley, Union Square did not push for a move south of the border.

“Clearly they are attracting and recruiting the good people and, if [Toronto is] their home base, they should stay where they want to stay,” Mr. Weissman said.

In recent years, the venture capital firm also looked at applying lessons from social networks to specific disciplines like healthcare and invested in Human Dx, a social network meant to devise medical solutions through machine learning.

It was mainly the calibre of the team that drew angel investor Daniel Debow, co-founder of Rypple, to reinvest in Figure 1. Mr. Levey, a former journalist and now communications professor at Ryerson University, had hashed out the idea with mobile developer Richard Penner and critical care doctor Joshua Landy, who experienced the need for the app firsthand.

“What’s beautiful about this was, we had this behaviour — Instagramming, sharing photos — and we already had doctors doing this [sharing photos of particular cases] but not on any approved platform. And these guys figured out how to take advantage of it,” Mr. Debow said.

“They seemed like really smart guys. Just the right combination of humility and hussle.”

Adam Bretholz, an emergency pediatric doctor at the Montreal Children’s Hospital, was one of the early adopters of Figure 1. “Before, I’d Google image things like anybody else,” said the doctor, who also teaches medicine at McGill University. He emphasized that the average person would not be able to filter through the “garbage” that saturates the search engine.

“The level of discussion around [Figure 1’s] images is so very helpful for learners and for physicians who seek some feedback.”

The app, available for iPhone and Android, verifies users’ credentials and extends different user privileges to avoid having non-experts spread false information, as is sometimes the case with Wikipedia, where nearly anyone can access and edit entries.

Mr. Bretholz said it’s useful to crowdsource and obtain feedback about a potential diagnosis on this privacy and consent-driven platform, highlighting that personally identifiable details on patient photos are blurred out and that patients must give consent through a sophisticated in-app form.

At a staff meeting in September, he intends to push for a broader use of the app in his workplace, one of North America’s busiest emergency pediatric departments. Currently, about 17% of Canada’s medical students use Figure 1 as an learning tool.

Mr. Levey said he is in no rush to monetize the app but hopes the new funding will help the startup grow its 10-employee team, add new features to its app and, after adjusting it to foreign languages, privacy laws and healthcare norms, expand to other countries.